The subject application relates to latent image formation in xerographic systems. While the systems and methods described herein relate to image formation in xerographic systems, it will be appreciated that the described techniques may find application in other image formation systems, other xerographic applications, and/or other imaging methods.
Approaches to photoreceptor-based xerography have included using high-mobility transport layers, light-absorbing additives, anti-reflective substrates, and addressable LED or LCD light sources.
Classical latent image formation in xerography consists of the following steps: charging the surface of the imaging member (e.g., a photoreceptor) with corona to create background surface potential; photo-generating free charge carriers within the areas that need to be toned; and changing surface potential in these areas by transporting photo-generated charge towards the surface.
In analog or light-lens xerography, using the light reflected from the original image to photo-generate electric charge in a photosensitive imaging member is the conventional way to convert an original image into a latent image. In digital xerography, however, the original image is already digitally encoded, and therefore can be converted into various types of signal. The concept of using light to write a latent image onto a photosensitive imaging member was simply inherited from light-lens xerography, but it is not the only possible way to generate a latent image.
Disadvantages of photoreceptor-based xerography include low charge mobility, sensitivity to light shock, and the need of an expensive light source such as a raster output scanner (ROS) (e.g., a laser) that occupies a considerable space in the system and adds greatly to its cost. Additionally, exposure to a laser beam is associated with various parasitic effects that cause image distortion and limit resolution (see, e.g., Journal of Imaging Sci. and Tech, vol. 40, p. 327, 1996)
U.S. Pat. No. 6,100,909 (Haas and Kubby) describes an apparatus for forming an imaging member comprising an array of high voltage thin-film transistors (TFT) and capacitors. A latent image directly formed by applying appropriate DC bias to the TFT using a high-voltage power supply (HVPS) and charged-area detection (CAD)-type development.
Accordingly, there is an unmet need for systems and/or methods that facilitate using photodischarge for surface potential reduction and TFT control for latent image formation on an imaging member, while overcoming the aforementioned deficiencies.